We examined the belt and where it tore apart the belt had been blistered by heat. This did not happen due to running but when the engine stopped, and like all gas engines they have a tendency to stop at the exact same place due to compression differences. So the belt stopped at the exact same location on the crankshaft and got cooked.
Michael,
In theory this sounds plausible, but in practice I highly doubt it.
You are correct that motors tend to stop at the same degrees of rotation of the crank. The lower the number of cylinders the more precise that becomes.
I couldn't count the crank pulley teeth, but I was able to get what I think is a good count on the cam pulley teeth. I counted 38 and the crank runs at twice the speed of the cam so it has to be a 19th. I guess it really doesn't matter, but in my mind I thought it would...
The crank pulley on the S&S is 19 teeth and the belt pitch is 127 so the relationship of the crank pulley to any given spot on the belt is going to be purely random and it's very unlikely to repeat, let alone on every start/stop cycle of the motor. It takes 6.684 revs of the crank to make it once around the timing belt.
I don't disagree about the build up of heat inside the case. Even decades ago when Harley did the belt primary they had a vented cover to help reduce the heat on the belt. And that was outside the motor, not inside. Without some type of venting/cooling, I cannot believe these belts last very long on average.
I like the idea of scoops to cover the direct holes and still let air flow through the cover.
